Polarity-indicating mechanism for x-ray apparatus.



C. FAYER.

POLARITY INDICATING MECHANISM FOR X-RAY APPARATUS.

APPLICAHON FILED MAY l8- I9I6.

1,266,931 Patented May 21,1918.

2 SHEETS-SHE I.

a/Ma A414 MW A TTORNEY C. FAYER.

POLARITY INDICATING MECHANISM FOR X-RAY APPARATUS.

APPLICATION FILED HAY I3. I916.

1,266,931. Patented May 21,1918.

2 SHEETS-SNEEI 2.

1/ 44 ikyd/ INVENTOR. 4) (fiarlar Payer 44 BY M116; {1M I 6' 7 ATTORNEY UNITED STATES PATENT omen.

CHARLES IAYER, OF NEW YORK, N. Y., 488161103 T0 WAPPLEB ELEOTBIG COMPANY, 1116., A CORPORATION 03' K EW YORK.

POLABI'I'Y-H'DIGA'IING MEOHANIBM FOB Z-BAY APPARATUS.

Specification of Letters Patent.

Patented May 21, 1918.

Application filed Kay 18, 1816. Serial No. 98,485.

To all whom it ma concern:

. Be it known t atl, CHARLES FAYER, a citizen of the United States, residing in the city of New York, borough of Bronx, in the county of Bronx and State of New York, have invented new and useful Improvements in Polarity-Indicating Mechanisms for X-Ray Apparatus, of which the followinglis a full, clear, and exact description. invention relates to X-ray a paratus n w ich 9. hi h potential current discharge 15 sent throug an X-ray vacuum tube, and in which the said discharge, owing to the manner of its production, may tend to follow either of two directions, whereas for safety of the tube the discharge when sent through it must always follow, relatively to the tube, the same direction.

My invention enables the operator, 'by merely readin an indicator at any time, and particular y-at the moment before the commencement of the high potential current discharge through the X-ray tube, to deter mine which of two directions through the tube the discharge tends to follow.

My invention also enables the operator, after reading the indicator as just mentioned, to instantly control the discharge circuit so as to reverse the direction the discharge tends to take, and thus prevent disaster to the X-ray tube when the discharge passes through it.

My device is of peculiar. service where the discharges are made from currents sup- 1 "plied by a transformer and controlled by a rectifying disk rotated by a synchronous motor, this motor being driven by alternating currents from the circuit feeding the transformer. Such mechanism is shown, for example, in Patent No. 992,302, dated May 16, 1911, to Reinhold H. Wappler.

Very often in such apparatus there is a rectifying disk carrying two commutator sectors, and driven at, say, 1800 revolutions per minute by a single-phase synchronous motor. Here the currents delivered b the rectifying disk may have either of two irections, for the reason that under diiferent starting conditions the rectifying disk may occupy either of two different angular positions at the precise moment when the field of the motor is energized by current flowing through it in a given direction.

When my invention is used with apparatus Fig. 2, but occupyin of the type just mentioned the operator, after reading the indicator as above described, ma if necessary reverse the direction in which the discharge is taking place, or in which it tends to take place, as the case may be.

My invention consists of various parts and combinations of mechanism, for attainin the particular objects above mentioned an others, all tending towardimprovement in the general efliciencv of the apparatus.

Reference is made to the accompanying drawings formin a part of this specification, and in whic like letters indicate like parts in all of the figures.

Figure 1 is a diagrammatic-pars ective showing my improved indicating mec anism as used upon an X-ray machine.

Fig. 2 1s a fragmentary diagram of certain revoluble parts shown at the left of positions different from those indicated t erein.

Fig. 3 is a fragmentary diagram of the parts shown in Fig. 2, but showing the same as moved into different positions from those indicated in said Fig. 2.

Fig. 4 is still another view of the parts appearing in Fig. 2, but showing them as shifted still further and into different positions.

Fig. 5 is a graphic representation of the potential variations takin place in the indicator circuit as contro ed by the commutator mechanism.

Fig. 6 is a longitudinal section through the armature of the synchronous motor, and parts carried by such armature.

Fig. 7 is a side elevation of the synchronous motor anh rectifying disk, to other with my im roved' commutatin mec anism for control ing the indicator circuit.

Fig, 8 is a fragmentary end elevation of the mechanism shown in Fig. 7.

Fig. 9 is a view, artly in elevation and partly in section, 0 my improved commutator ringforming part of the mechanism for controlling the indicator circuit.

Fig. 10 is a section on the line 1010 of Fig. 9, looking in the direction of the arrows.

Fig. 11 is a sectional view of a commutator brush anda plate for supporting the same, these being arts ofthe mechanism for controlling the indicator circuit.

switch 42, connected with the therefrom as hereinafter described A pair of alternating current mains are shown at 12, 13, and at 14 is a high-potential transformer the primary winding 15 of which is bridged across the mains by wires 16, 17. A hand switch 18 may be used if desired, for throwing the transformer into and out of action.

The secondary winding of the transformer appears at 19, and from it wires 20, 21, lead to brushes 22 23.

Adjacent these two brushes is a rectifying disk 24, preferably of micanite, adapted to make 1800 revolutions per minute. Two other brushes appear at 25, 26, and from the brush 26 a wire 27 leads to a spark terminal 28. A wire 29 leads from the brush 25 to another spark terminal 30. The X-ray tube (not shown) is placed between the terminals 28, 30. The disk 24 carries a pair of commutator sectors 31, 32 which are engaged by the brushes as the disk is rotated. The brushes are mounted upon a board 33.

The disk 24 is secured rigidly upon a shaft 34, which is the armature shaft of a motor 35. This is a synchronous motor-of the type sometimes designated as a Tesla motorand in this instance is of single phase. It has a rotor armature 86, a starting field 37 and a running field 38, these parts being ofthe usual or any desired construction. The running field is, by wires 39, 40, bridged across the mains 12, 13, and the field 37 is connected to the field 38. A hand wire 40, is used for opening the circuit throu h tne field 38. A wire 41 leads from the eld 37 to a button switch 42, and from the latter a wire 43 leads to the wire 39. The button switch 42 is normally open, so that normally the running field 38 alone is in circuit wit the mains. When the button switch is closed however, both the starting field 37 and e r' field 38,.in parallel with each other, are in circuit. As a result the closing of the button switch 42 disturbs the distribution of the magnetic field relatively to the armature, and causes the wave to skip one step. I find that in ractice each time the button switch is c osed, even for an instant the armature and with it the rectifying disk, is retarded or set back ninety deees. This retardation causes a reversal in t c direction of the rectifial currents being delivered, or to be delivered, as the case ma be, from the rectifying to the sparl i The use of the button switch 42 is merely illustrative of one way in which the field clarity may be reversed. .If desired the eld polarity may be reversed in any other suitable manner. Mounted upon the armature shaft and revoluble therewith, but spaced concentrically are a 66 pair of metallic sectors 44, 45, separated by Eotential variations taking sector blocks '46, 47 of insulating material. A pair of brushes 48, 49 engage the sectors 45, and are spaced angular] apart, in the direction of rotation of the sectors, by ninety degrees. A wire 50extends from the brush 45 to an indicator 51 of a ty e suitable for determining the direction 0 a current through it, and for this purpose is provided with a ointer 52. T e indicator is further providbd with a resistance coil 53 for protecting it and reventing it from short-circuiting the mains. This indicator may be of ordinary construction. It is connected by a wire 54 with the main 12. A wire 55 extends from the brush 48 to the main 13.

The forms of various mechanical parts may be understood from Figs. 6 to 11 inclusive.

The motor 35 rests upon any appropriate support 56 and in this instance 18 rovided with a spider 57 forming a part of t e motor casing. Detachably secured u on this in mountin the sectors blocks 46, 4 I secure a on the armature 36, and fiber or other insulating material upon the metallic ring, as shown in Figs. 9 and 10. Next the sectors 44, 45 and sector blocks 46, 47 are placed upon the ring 64, and clamped in place b a second ring of insulating materia crews 66 extend through screw holes in the rings and through bushings 67 of insulating material, the latter extending through the sectors 44, 45. The parts are thus eld securely together, and in practice may be together treated composite ring to be mounted upon the armature.

The graph shown in Fig. 5 represents the lace in the inicator circuit. By .eonside these potential variations in connection with the action of the commutator mechanism consisting of cuit.

The operation of my device is as follows: The various parts assembled and arranged, I will suppose that at the start the apparatus has the condition indicated in Fig}. 1. The hand switch 18 is here closed, and t e button switch 42 is open. A hi h potential discharge is now passing from the terminal 30 to the terminal 28; and the pointer 52 is in its position toward the right of the indicator, Where it indicates that the direction of the spark discharge is, say, from right to left, according to this re.

he various circuits may be readily traced.

he primary circuit is as follows: main 12, wire 16, primary windin 15, wire 17, hand switch 18, main 13 to a ternating current generator (not shown), main 12.

A secondary circuit, of momentary duration, may be traced as follows: seconda winding 19, wire 20, ,brush 22, sector 31, brush 25, wire 29, terminal 30, thence across the spark gap (or through the X-ray tube) to the terminal 28, wire 27, brush 26, sector 32, brush 23 and wire 21, back to secondary winding 19.

The field circuit is wire 39, running field 13, thence to alternating generator shown) and back to main 12.

he indicator circuit, which remains unchanged for a moment only, is as follows: main l2, Wire 54, indicator 51, with its reslstancc winding 53, wire 50, brush. 49, sector as follows: main 12, 38, wire 40 to main (m moment is flowing. Thus the voltage affecting the indicator is represented at the curve marked and disposed at the left of Fig. 5, andthe pointer 52 remains steadfast in the position in which it is shown.

The next step in the automatic action of t e apparatus is a reversal in the direction of the current energizing the mains 1 2, 13, and thisreversal of the current mentioned is accompanied by a rotation of ninety degrees in the armature shaft and all parts carries thereby, in a clockwise'direction ac- 1, so that the parts thus ro- This brin cults. The circuit through the primary winding about some changes in the cir- 15 of the transformer 14 is the Same as" above traced, but t rent through the momentarily reversed.

A secondary circuit, of momentary dura-] tion only, mav be traced as follows: secondc direction of the curary winding 19, wire 21, brush 23, Sector 31 (see Fig. 2), brush 25, wire 29, terminal 30,

X-ray tube (not shown), terminal 28, wire (See Fig. 2) brush 27, brush 26, sector 32 22, and wire 20 back to secon 19. The high potential discha e, formi a part of the circuit just traced, as now the same direction as at the start, because aldary winding though the induced current from the secs ondary winding 19 has now a reversed direction relatively to the winding, its direction for purposes of the terminals 30 and 28 is thence to the indicator in the primary winding is now rectified by the chan e in positionof the sectors 31, 32. In at er words, the dlrection of the high potential discharge throu h the X-ray tube is rendered normal by t e action of the recti i disk.

The indicator circuit, however, is now open as the sector 44 engages the brush 48 and the sector 45 engages the brush 49, there being no conductive connection from one sector to the other. If the. current could now flow through the would be reversed relatively to its direction of flow according to Fig. 3,, and hence would be graphically represented by the second curve, marked and dis osed below the median line in Fig. 5. T is fact is here pointed out merely as a means of bearing 1n mind the chan 'ng phase relations of the various movab e parts. No current now:

passing through the indicator, or at least 3,1, and also brings the sector 45 into the position originally occupied by the sector 44. These changes, together with the fact that the flow of theprimary current is now in the same direction as in the beginning, brings the entire apparatus into a condition substantially identical with that disclosed in Fig. 1. Therefore the discharge between I the terminals 30 and 28 is in the same direction as before; current now flows throu h same direction as 1n Flg. 1, this current having the maximum v0 tage of the mains, and hence being raphically represented in Fig. 5 by the t ird curve from the left thereof, marked The "pointer 52 therefore stiltremains steadfast 1n its original position indicated inFig.1.

The action of the mechanism being continned'still further the armature assumes the position indicated in Fig. 4, which is close] analogous to that indicated in Fig. 2, and for purposes of all electrical results may he considered as identical therewith.

Therefore the indicator circuit is open, the pointer 52 still remains in its extreme position at the right, as shown, and the condi tions of the voltage and current which would obtain in this circuit if closed are shown graphically by the curve at the extreme t, marked in Fig. 5.

/ 0 long as the button switch remains undisturbed, the high potentialdischarges all have the same direction, and the pointer 52 remains in a fixed position associated with such direction.

Suppose, next, that the mechanism is in the condition shown in Fig. 1, and that the operator momentarily closes the button switch. This completes a circuit as follows: Main 12, wire 39 whence the current divides, a part passing to the field 38 and a part passing through the wire 43 button switch 42 and wire 1 to the field 3 7, the two portions of the current thence uniting, wire 40, main 13 to alternating generator (not shown) to main 12. This circuit energizes the two fields 37 38 in parallel, and by so doing disturbs the ton switch after being closed momentarily is opened immediately so that the field 3 is deenergized, the original condition of the magnetic torque is restored, and the armature after being thrown out of step is again brought into step, but as no corresponding change is made in the phases of the line current the armature is retarded, or displaced angularly backward as compared with the position it would otherwise occupy,

' lows: main 13, switch byoexactly one quarter of a revolution as 9. ve' explained.

Since, therefore, the armature normally makes one complete revolution while the current in the mains 12, 13 makes four reversals or two complete cycles, the above-described angular displacement of the arma-,

ture has relatively the same. effect as a reversal in direction of the current flowing in the mains 12, 13, without any corresponding change in the position of the armature.

or convenience in further tracing the circuits I will again refer to Fig. 1, and will consider that owing to a momentary closure of the button switch 42 the direction of flow of current in the mains 12, 13 is now reversed, without any corresponding change being made in the position of the armature and rectifying disk.

The-primar circuit, unchanged except as to direction 0 the flow of current, is as fol- 18, wire 17, primary winding 15 wire 16 main 12, to dynamo (not showns, thence back to main 13.

A secondary circuit, of momentary duration, may be traced as follows: secondary winding 19, wire 21, brush 23, sector 32, brush 26, wire 27, terminal 28, X-ray tube (not shown), terminal 30, wire 29, brush 25, sector 31, brush 22, and wire 20, back to primary winding 19. This circuit causes a high potential current discharge to take place through the X-ray tube in the direction from the terminal 28 to the terminal 30-that is, in the direction contrary to the one first contemplated.

'Further rotation of the armature shaft will bring the rectifying disk successively into the positions indicated in Figs. 2, 3 and distribution of the magnetic field and the magnetic torque thereof. The but- 4, and the circuits will be the same as above traced with reference to these figures, thou h in each instance the current will be in t e contrary direction to the one previously contemplated. Hence all of the high potential current discharges now ass from left to right, from the termina 28 through the X-ray tube to the terminal 30.

Referring again to Fig. 1 and bearing in mind the reversal in the flow of current through the mains 12, 13, due to the momentary closure of the button switch 42 above mentioned, the field circuit is as follows:

main 13, wire 40, running field 38, wire. 39 to alternating generator, thence to main 12.

The indicator circuit, which remains unchanged for a moment only, is as follows: main 13, wire 55, brush 58, sector 45, wire 50, indicator 51, wire 54, main 12, dynamo (not sh Am) and main 13. Since the current in the mains is now for the moment flowing in a direction contrary to the one first contemplated, the indicator is affected accordingly, and the pointer 52 swings to the left and takes up the new position indicated by dotted lines.

As the armature continues its rotation, so that the various revoluble parts assume progressively difierent positions as indicated in Figs. 2, 3 and 4, the alternations of the current through the mains 12, 13 are of course accompanied by rectifications of the hi h potential current discharges, due to the ordinary work of the rectifying disk, and the indicator will persistently registenthe same indication so long as nofurther change is brought about.

Each time the button switch is closed and opened, therefore, the direction of the high potential current discharge is reversed, and a corresponding indication is made and persistently registered by the indicator-the deflection of the pointer in one of two directions being a guide for disclosing the direction in which the hi h potential current discharge tends to take place.

By the use of my apparatus the operator can readily avoid the danger of e osing valuable X-ray tubes to the action 0 high potential current discharges flowing in the wrong direction.

'In practice the operator places the X-ray tube in position, starts the motor into action and ma es his reading of the indicator before he allows the high potential current discharges to take place through the tube.

He can control time of the high potential discharges by throwing the transformer into and out of action in use of the hand switch 18 or in any other esired manner.

My device can be used to advantage as an attachment for X-ray machines, but if preferred it can be permanently incorporated in the machine.

I do not limit myself to the precise construction shown, as Variations may be made therefrom without departing from the spirit of my invention.

claim 1. In an apparatus of the character described the combination of alternating current mains, a step-up transformer connected with said mains and thereby energized, a rectifying switch connected with said transformer and energized thereby for delivering high potential discharges of unitary but uncertain direction, a synchronous motor connected with said alternating currentmains and energized thereby for actuating said rectifying switch, means for indicating the direction of said high lpotential discharg and mechanism contro able at the will b? the operator for momentarily retarding the speed of said synchronous motor relatively to the frequency of the phasal changes in said alternating current mains.

2. In an apparatus of the character described the combination of a pair of alterna current mains, a primary circuit bri d d across said mains and adapted to be energized thereby, a secondary circuit inductlvely cou led to said primary circuit and energiz thereb for producing high potential current arges, rectifying mechanism connected with said secondary circuit in order to said discharges, a synchronous motor, sa1 motor being connected with said mechanism in order to actuate the latter, a commutator driven by said motor and connected with said alternating current mains by a circuit bridged across said mains independently of said prima circuit, for selectively divert ing from said alternating mains currents of unitary direction, an indicator electrically connected to said commutator in order to in dicate the direction of said currents, and means controllable at the will of the opera-. tor for momentarily retarding the action of the motor as related to the time of the current phase in the alternating current mains.

3. In an apparatus of the character described the combination of a pair of alternating current mains, a transformer connected with said mains and energized thereby for producing high potential discharges, a rectifying switch connected to said transformer and coacting therewith to render the discharges of unitary but uncertain direction, a synchronous motor connected with said alternatmg current mains and energized thereby, a revoluble shaft connected with said motor and with said rectifying switch for enabling said rectifying switch to be driven, a commutator carried by said revoluble shaft, a circuit bridged across said alternating current mains independently of the connection of said motor to said mains, said circuit bein connected with said commutator and controllable thereby for selectivel diverting currents of unitary but uncertam direction from said mains, an indicator for disclosing the direction of flow of said currents, and means controllable at the will of speed of said motor relatively to the frequency of the phasal changes in said alternating current mains,

CHARLES FAYER.

the operator for moment y retarding the- 

